Comparison of Sewage Sludge and Yard Waste Compost As Biofilter Material for Ammonia Removal

Sewage sludge compost and yard waste compost were compared with respect to their efficiency as biofilter material for removing ammonia from air. Ammonia removal efficiency was investigated using both small-scale filter columns in the laboratory and large-scale filter columns operated at a pig farm. The laboratory experiments were carried out using 30 cm high columns with a volume of 250 cm³ supplied with an artificially produced ammonia-air mixture, whereas 1 m columns with a volume of 27 liters supplied with the ambient air from the pig stable were used in the large-scale experiments. All filter columns were able to remove more than 95% of the ammonia in the inlet regardless of compost type and applied air flow rate. Ammonia concentration profiles inside the compost columns measured at the end of the experiments indicated that sewage sludge compost removes ammonia at significantly higher specific rates than yard waste compost. The likely explanation is that sewage sludge compost contains higher numbers of nitrifying bacteria originating from the wastewater treatment process.     

Growth of Impatiens ‘Accent Red’ In Three Compost Products

Growth of Impatiens wallerana Hook. ‘Accent Red’ was evaluated in three composted urban waste materials (composted biosolids and yard trash (SYT): 20 percent biosolids/sewage sludge, 44 percent yard trimmings, and 36 percent mixed paper; composted refuse fuel residues with biosolids and yard trash (RYT): 74 percent refuse-derived fuel residuals, 10 percent biosolids/sewage sludge, and 16 percent yard trimmings; and composted municipal solid waste (MSW): 100 percent municipal solid waste). Treatments consisted of 100 percent composted waste and media in which the composted wastes were combined with control medium components at 60 percent, 30 percent, or 0 percent composted waste, by volume. Shoot dry mass of plants grown in SYT increased as the percentage of SYT in the medium increased, while shoot dry mass of plants grown in MSW linearly decreased from 1.24 g to 0.15 g. There were no significant differences in shoot dry mass of plants grown in different percentages of RYT. Initial medium soluble salt concentrations in MSW media were more than double concentrations measured in SYT and RYT media. Soluble salt concentrations in both the 100 percent and 60 percent MSW media exceeded 1.75 dS.m^?1, while the soluble salt concentrations in 100 percent SYT and 100 percent RYT were 0.50 dS.m^?1 and 0.61 dS.m^?1, respectively. The C:N ratios in 100 percent SYT and RYT were 17 and 15, respectively, while 100 percent MSW had a C:N ratio of 29. The relatively higher level of compost maturity as indicated by lower C:N and soluble salt concentrations contributed to superior growth of impatiens plants in 100 percent SYT and RYT compared to 100 percent MSW.     

Pesticide Screening in a Commercial Yard Waste And Biosolids Compost

The presence of pesticides in compost is of interest because of possible health, production and ecological risks. The presence of over 50 pesticides was assessed in raw yard waste, milled yard waste, and a finished compost (yard waste:biosolids) at a commercial compost facility in Florida. These pesticides were comprised of 38 herbicides, eight insecticides and two fungicides. Of the pesticides monitored for in this study, only atrazine, 4,4-DDE, alpha chlordane, gamma chlordane, and endosulfan I were detected, and were only present in raw yard wastes.     

Pesticides in Yard Waste Compost

Samples from six yard waste composting facilities in New Jersey were analyzed for a wide range of pesticide residues. Chlordane was found at low levels (0.3-3.2 mg/kg) in all samples; no other pesticide was detected. It appears likely that the source of the chlordane is the residential soil incorporated with the raw yard waste during collection. Based on these findings, routine analysis of yard waste compost for pesticide residues does not appear warranted.     

Regeneration of Nitrogen Fertility In Disturbed Soils Using Composts

Soil disturbance often results in loss of soil organic matter and nitrogen (N) fertility, making revegetation of barren areas difficult. Yard waste composts are a potential source material to regenerate soil fertility so that revegetation success is improved. The N release behaviors of several compost materials produced within California were evaluated during a long-term, 586-day aerobic incubation. Two general types of compost were tested, including yard waste compost materials (lawn clippings and chipped brush) and cocomposted materials (biosolids bulked and composted with yard waste materials). Nitrogen release from composted material was measured using periodic soil solution extraction and soluble N analysis. Nitrogen release rates varied widely between source materials during the initial portions of the incubation period, with cocomposts having much greater release rates than the yard waste composts. Yard waste composts that were poorly cured or had high woody fiber content showed net immobilization of N during the initial incubation periods, which could potentially lead to N-limitations for plant growth in field conditions. Following additional curing in the soil, however, all yard waste compost materials had positive net N mineralization release rates. Release rates were similar to some of the native soils used as reference materials. The relationship of long-term aerobic N release and several other indicators of mineralizable or “bioavailable” N were evaluated, but the relationship of these other indicators with the aerobic incubation data was low. Because the cumulative N release from yard waste compost materials was a small fraction of the material's total N content, N leaching losses in field conditions are expected to be small and of short duration. Steady, long-term N release patterns were observed from composts throughout the second half of the study and would be expected to continue for an extended period in the field. Composts are shown to provide a suitable replacement source of slowly available N for plant establishment on drastically disturbed, low nutrient soils.     

Wood Ash as an Amendment in Municipal Sludge And Yard Waste Composting Processes

Wood ash from a wood-fired, electrical generating plant was examined as a potential amendment in municipal biosolids and yard waste composting applications. The rate of composting and the final compost quality (chemical, physical, and plant growth characteristics) were examined. Yard waste (leaves, grass, and wood chips) and a municipal biosolids-chip mixture were either not amended or amended with wood ash at eight percent or five percent by weight, respectively, and then composted outdoors in insulated, 1700L, aerated reactors. Yard waste piles heated rapidly to 60°C within six to seven days, whereas biosolid piles heated more slowly to a maximum of 52 to 57°C within nine to 11 days. Ash had little, if any, effect on the time-temperature response. In general, ash-amended compost had higher pi I, plant nutrient, and salt contents. Tomato plants (Lycopersicum esculentum) produced 100 percent more shoot biomass in biosolids than in yard waste compost media. Poor plant growth in the yard waste compost was likely due to the high initial pH and salt content of the growth medium. In yard waste media, tomato plants germinated and produced more shoot biomass in the control compost than in the ash-amended compost.

A pH neutralization study indicated that wood fly ash could be used as an economical substitute for lime which is commonly used to stabilize municipal biosolids prior to land filling or land application. Wood fly ash (pH = 13.2-13.4), when added to biosolids at a 2 to 1 ratio by weight, raised the pH of the mixture to 12.0.     

Degradation of DEHP,PAHs and LAS in Source Separated MSW and Sewage Sludge During Composting

The efficiency of composting to remove the pollutants DEHP, PAHs and LAS from organic waste products was investigated. Source separated MSW and sewage sludge, respectively, were composted at temperatures ranging from 35 to 70°C using a laboratory-scale reactor composting system. At regular intervals, compost samples were taken from the reactors for chemical analysis. DEHP disappeared rapidly during composting of MSW; 96 to 99% of the initial content was degraded within 25 days of composting regardless of process temperature. In sewage sludge, the highest degradation of 91% was reached at a composting temperature of 65°C. LAS degradation in sewage sludge was fastest at 55°C, but at both process temperatures tested 99% of the initial content had been removed within 25 days. Degradation of PAHs was less complete. However, in all composting experiments, with MSW as well as sewage sludge, the final PAH concentration was less than in the starting material. Further experiments suggested that less than 0.1% of the pollutants had evaporated. Thus, composting proved to be a promising technique to promote degradation of organic pollutants — especially DEHP and LAS — in MSW and sewage sludge.     

Biochar from Pyrolysis of Deinking Paper Sludge and Its Use in the Remediation of Zn‐polluted Soils

An increasing proportion of recycled fibres are used in paper industries. Removing the ink, clay, coatings and contaminants from paper waste in order to produce recycled fibres creates large amounts of deinking paper sludges. The preparation of biochar from pyrolysis of this waste and its use in soil remediation contaminated with heavy metals could be an interesting valorization alternative. Our aim was to study the influence of biochar from deinking paper sludge (HP) pyrolysis in the treatment of Zn‐polluted soils. Three different soils contaminated with 2000 mg Zn kg⁻¹ were amended at a rate of 10% with deinking paper sludge and deinking paper sludge biochar prepared at three different temperatures (300, 400 and 500 °C). Soils were incubated under laboratory conditions, and soluble Zn was measured. The addition of biochar reduced the amount of mobile Zn. Finally, Zn solubility decrease was more pronounced for biochars prepared at a higher temperature. Copyright © 2016 John Wiley & Sons, Ltd.     

Compost Use in Plant Nurseries: Hydrological and Physicochemical Characteristics

A study was conducted to collect, classify and analyze a large number of compost samples to establish a database for determining the relative quality of different types of composts and their potential use based on their hydrological and physicochemical characteristics. Special attention was devoted to the use of compost for flower growing, which extended the analysis to include substrates, such as peats and organic substrates for pot coltures. Some 64 samples of various composts were collected directly from production plants in northern Italy. Depending on the starting raw materials, compost samples were grouped in six categories: sludge compost; animal manure compost; slaughterhouse waste compost; source separated MSW compost; raw MSW compost and yard waste compost. At the same time, 52 samples chosen from among peats and organic substrates, for professional growers and amateur gardeners, were obtained or bought from greenhouses, garden centres and shops. Hydrological and physicochemical properties of the 116 samples (composts, peats and substrates) were determined including: easily available water (EAW), water buffering capacity, (WBC), air capacity, total porosity, bulk density, real density, pH, specific electrical conductivity, cation exchange capacity, organic carbon and ash     

Windrow Cocomposting of Municipal Biosolids and Yard Waste

A total of four windrows with yard waste:biosolids ratios ranging from 5.0:1 to 1.2:1 by wet weight were operated over a six month period. The windrows were monitored for temperature, oxygen content, bulk density, particle size, compost characteristics (including metals, nutrients, pesticides, volatile solids, and moisture content), runoff characteristics, and odor potential. Based on study results, cocomposting should be employed at a yard waste:biosolids ratio greater than or equal to 3:1 in order to minimize odor and improve compost characteristics. Leaching of several metals was observed; however, only lead was observed in the runoff at concentrations above maximum contaminant levels.     

Improvement of earthworm (Lumbricidae) community and activity in mine soils from open-cast coal mining by the application of different organic waste materials

Earthworms are important members of the decomposer food web in a wide range of sites. Previous field investigations on the development of earthworm populations of mine soils in the Lusatian coal mining region, Germany, have shown quite small population densities in quaternary sands and less or even no earthworms present in sandy soils derived from tertiary deposits. The aim of the present investigation was to improve the development of earthworm populations in mine soils from tertiary deposits by applying various types and amounts of organic waste residues, such as sewage sludge, composted sewage sludge, and green waste derived compost. Additionally, we were interested in the stimulation effect of organic waste materials on parameters of earthworm activity, such as food consumption and burrowing activity. The investigations were carried out in field mesocosms and laboratory experiments (microcosms; observation cages). In general, the population density, fresh biomass, food consumption, and the burrowing activity of earthworms were significantly improved by the application of the various organic waste materials compared with mineral fertilizers. Fresh sewage sludge in addition to composted sewage sludge were found to be the most favourable organic waste residues compared with green waste derived composts. The addition of brown coal sludge to sewage sludge did not reduced the stimulation effect. There was considerable variation in the population structure of a defined earthworm community which was exposed in the mesocosms during a two year period in relation to the types and amounts of the organic waste materials applied.     

Spectroscopic and thermal investigations on compost improved by iron salt addition

A quality compost obtained from sewage sludge (one part in weight) and yard trimmings and sawdust (two parts) has been investigated as a potential carrier of iron to plants. At the end of the thermophilic phase, the composting materials were added with crystalline FeSO4.7H2O (97%). Chemical properties, respiratory indices, and seed germination tests proved the compost to be suitable as an iron carrier in agriculture. Fourier transform infrared spectroscopy (FT-IR) and fluorescence spectroscopy provided evidence of the effective linking of the iron ion to the organic molecule functional groups, thus preventing the loss of iron ion by leaching and precipitation phenomena and allowing the metal ion to be available to plants as both mineral and organic species. The thermogram obtained on compost without iron was similar to that previously obtained for composted materials of different origins, whereas samples with added iron ion exhibited in addition an exotherm in the medium-temperature region. FT-IR spectra carried out on samples heated at different temperatures indicated a loss of iron ion linked to carboxyl groups.     

Recycling of sewage sludge and household compost to arable land: fate and effects of organic contaminants, and impact on soil fertility

Effective use of organic wastes for agricultural production requires that risks and benefits be documented. Two types of sewage sludge, household compost and solid pig manure were studied under field and greenhouse conditions to describe their fertilizer value and effects on soil properties and soil biota, the fate of selected organic contaminants, and their potential for plant uptake. A 3-year field trial on two soil types showed no adverse effects of waste amendment on crop growth, and a significant fertilizer value of one sludge type. Accumulation of N and P_i was indicated, as well as some stimulation of biological activity and micro-arthropod populations, but these effects differed between soil types. There was no detectable accumulation of polycyclic aromatic hydrocarbons (PAH), di(2-ethylhexyl)phthalate (DEHP), nonylphenol and ethoxylates (NP+NPE) or linear alkylbenzene sulfonates (LAS) after three repeated waste applications, and no plant uptake was suggested by analysis of the third crop. A plot experiment with banded sludge was conducted to examine sludge turnover and toxicity in detail. Less than 5% of NP or LAS applied in organic wastes was recovered after 6 months, and less than 6% of DEHP applied was recovered after 12 months. Potential ammonium oxidation (PAO) at 0–1 cm distance from the banded sludge was stimulated despite toxic concentrations in the sludge, which suggested that contaminants were degraded inside sludge particles. Phospholipid fatty acid (PLFA) profiles suggested a gradual shift in the composition of the microbial community within sludge, partly due to a depletion of degradable substrates. A pot experiment with sludge-amended soil and soil spiked with contaminants showed no plant uptake of NP, DEHP or LAS. Degradation of LAS and NP added in sludge was delayed and the degradation of DEHP was faster than when the contaminants were added directly to the soil. In conclusion, adverse effects of organic waste application on soil or crop were not found in this study, and for some waste products positive effects were observed.     

The physical state of finely dispersed soil-like systems with drilling sludge as an example

The physical state and its dynamics were studied at the quantitative level for drilling sludge (finely dispersed waste of the oil industry). Using original methodological approaches, the main hydrophysical and technological properties of sludge samples were assessed for the first time, including the water retention curve, the specific surface, the water conductivity, the electrical conductivity, the porosity dynamics during shrinkage, the water yield, etc., which are used in the current models of water transfer and the behavior of these soil-like objects under real thermodynamic conditions. The technologically unfavorable phenomenon of the spontaneous swelling of sludge during the storage of drilling waste was theoretically explained. The water regime of the homogeneous 0.5-m thick drilling sludge layer under the free gravity outflow and permanent evaporation of water from the surface was analyzed using the HYDRUS-1D model. The high water retention capacity and the low water conductivity and water yield of sludge do not allow their drying to the three-phase state (with the entry of air) acceptable for terrestrial plants under humid climatic conditions, which explains the spontaneous transformation of sludge pits to only hydromorphic ecosystems.     

Organic Amendment Effects on the Transformation and Fractionation of Aluminum in Acidic Sandy Soil

Addition of organic amendments can alleviate the level of aluminum (Al) phytotoxicity in acid soils by affecting the nature and quantity of Al species. This study evaluated the transformation of Al in an acidic sandy Alaquod soil amended with composts (10 and 50 g kg^?1 soil of yard waste, yard + municipal waste, GreenEdge^®, and synthetic humic acid) based on soil Al fractionation by single and sequential extractions. Though the organic compost amendments increased total Al in soil, they alleviated Al potential toxicity in acidic soil by increasing soil pH and converting exchangeable Al to organically bound and other noncrystalline fractions, stressing the benefits of amending composts to improve acid soil fertility. The single‐extraction method appears to be more reliable for exchangeable Al than sequential extraction because of the use of nonbuffered pH extract solution.     

Systemic Resistance Induced in Cucumber Against Pythium Root Rot by Source Separated Household Waste And Yard Trimmings Composts

Disease control with compost often is attributed to four factors including competition, antibiosis, parasitism and induced systemic resistance (ISR). Induction of systemic resistance by source separated household waste and yard trimmings compost against Pythium root rot of cucumber caused by Pythium ultimum was studied in a split-root bioassay. Split-root pairings were tested in root rot potting soil paired with potting soil, compost-amended potting soil suppressive to root rot paired with the potting soil, and compost-amended potting soil paired with the compost-amended potting soil. Only one side of the split roots was infested with P. ultimum. Root rot, based on dry and fresh root weights, was significantly reduced in split roots of plants produced in the conducive infested potting soil paired with the suppressive yard trimmings compost-amended mix. This suggested that systemic effects were induced in the roots by the suppressive compost against Pythium root rot. Growth of transplants germinated in the source separated household waste compost mix was significantly better than those germinated in the potting soil. Finally, root rot of plants germinated in the suppressive mix and then transplanted into the conducive mix was also significantly less severe than that of plants germinated in the conducive mix.     

Changes in the microbial activity of an arid soil amended with urban organic wastes

Changes produced in the biological characteristics of an arid soil by the addition of various urban wastes (municipal solid waste, sewage sludge and compost) at different doses, were evaluated during a 360-day incubation experiment. The addition of organic materials to the soil increased the values of biomass carbon, basal respiration, biomass C/total organic C ratio and metabolic quotient (qCO₂), indicating the activation of soil microorganisms. These biological parameters showed a decreasing tendency with time. Nevertheless, their values in amended soils were higher than in control soil, which clearly indicates the improvement of soil biological quality brought about by the organic amendment. This favorable effect on soil biological activity was more noticeable with the addition of fresh wastes (municipal solid waste or sewage sludge) than with compost. In turn, this effect was more permanent when the soil was amended with municipal solid waste than when it was amended with sewage sludge. Received: 28 May 1996     

A Kinetic Model of the Yard Waste Composting Process

A new kinetic concept was applied to the yard waste composting process. Yard waste mixtures with different fractions of grass clippings were composted in pilot-scale vessels. Ammonia emissions were highest with high fractions of grass clippings. Calculation of reaction rate constants was based on heat and materials balances. Although the compost mass ratios (a dimensionless number that describes how far the process has advanced) of the mixtures after composting were similar, their chemical and biological analyses reveal differences. A first order reaction model is presented that can be used for plant design. The effects of temperature and particle size on process kinetics need to be investigated further.     

Speciation of Aluminum in Solution of an Acidic Sandy Soil Amended with Organic Composts

The effects of organic amendments (10 and 50 g/kg soil of yard waste, yard + municipal waste, GreenEdge, and synthetic humic acid) on soil chemical properties related to aluminum (Al) phytotoxicity and nutrient availability were evaluated. Compost amendment increased Mehlich 3–extractable calcium (Ca), magnesium (Mg), phosphorus (P), and potassium (K) in the soil by 3.5–260 times. No significant effect of composts on total Al in solution was observed. Organic amendments increased solution pH and decreased the activities of phytotoxic Al species to less than the critical levels, as a result of the formation of aluminate and humic acid–Al complexes. Low‐molecular‐weight organic acids were not effective in forming complexes with Al. Application of composts increased the concentrations of most nutrients in soil solution, suggesting a potential for ameliorating subsoil, but care must be taken to avoid nitrogen (N) and P leaching. Amending composts to acidic soils appears a useful strategy for diminishing Al phytotoxicity potential and improving soil fertility.     

Reactions of chrome tannery sludge with organic and mineral soils

Chrome tannery sludge applied to agricultural land may have benefits in terms of added N for crop growth. An experiment was designed to compare tannery waste with commercial N fertilizer and investigate the potential of the waste as an alternative or supplement to commercial fertilizer. Soils with 38% and 7% organic C and N content of 1.3% and 0.2%, respectively, were amended with lime, commercial N fertilizer, or tannery sludge containing 1.6% Cr. A portion of the tannery waste was supplemented with additional Cr 3⁺ salt before adding to the soils. The amended soils were analyzed for total Cr, ammonium acetate extractable Cr, selected nutrient and trace element concentrations. The tannery sludge increased soil pH, total Cr and N, S, Ca, P, Mg, and Na concentrations. DTPA extractable Cr increased only when Cr³⁺ salt was added, but soil pH decreased markedly. Electroconductivity of the soils increased with the waste application rate and, at the highest rate of Cr³⁺ salt addition, far exceeded values recommended for successful crop production. The acidic, high salt conditions complicated interpretation of the Cr³⁺ salt addition results. Tannery sludge may be applied to agricultural land as a fertilizer amendment without adversely affecting soil chemical properties. The amount and frequency of application should be determined by (1) total and available N, (2) total salt content, (3) total and available Cr, and (4) soil organic matter.